Anhydrous formic acid solutions of polypyrrolidone



'Unimd atent,

served with a preferred concentration of' l.5 parts formic 1 gt 2 A tit-t e Wi erex rem u i e fi l'i yt 'war r; ANHYDROUS sermons-m Sllchfihnt be j POLYPYRROL ONE 1 Carl E.' Barne's,Gloucester, William OL'Ney, In, Provi I V dence, and'William R.:Nummy, Wiif'in,"R. 1., assignors .to Arnold,.Holfman & Co., Incorporated, Providence, R. I.,'a' -corporationof RhodefIslaiid .No Drawing. Application February 2 4, 1 95 Serial No. 338,553 a 6 (Cl. 260-31.2) v

t way stretched.-fiSuch spinning solutions may have in v The present invention relates to polymer compositions and, more particularly, to new anduseful compositions containing polypyrrolidone. I i

The principal object of the inventionis the provision of highly useful solutions of .polypyrrolidone. Another f the-mass may be effected. iOther uses forthe, solutions naturaljor synthetic fibersand filaments, e. g), nylon, cotand more specific object of the invention is to provide ton, .wo'ol; rayon, glass andthe'likqassuch, or inlfabric' /form,; and aqueous dispersions andyemulsions prepared with the aid of appropriate "dispersing oruiemulsifying V polypyrrolidone solutions which are'particularly adapted for the production of improved polypyrrolidone films and fibers, although suitable for a variety of other uses.

Further objects will appear hereinafter.

agents for use as textileassistants and the like,

present invention, by virtue of the discovery that solu} tions of polypyrrolidone in at least substantially anhy drous formic acid, and containing, by weight not. more than three parts of formic acid per part of polypyrroli otherwise satisfactory films and fibers cannot be obtained therefrom. Except for the'above-stated limitation, which is critical to success of the invention, the quantity of polypyrrolidone may be varied over wide limits. G enerally speaking,however,. a practical lower limit of about 40 1.2 parts offormic acid for each part of polymer is ob- I removed from the glass without tearing.

.. Erqmp l e ll acid to each part of polymer.

Polypyrrolidone possessing film and fiber forming charsolution there was obtained. a slightly opaque butf expyrrolidone.

acteristics suitable for use in the present-invention is tremely tough and otherwise satisfactory." foil of polydescribed in the copending application'of Ney, Nummy. and Barnes, Serial No. 260,558, filed December 7, 19:51; now issued as U. S. Patent 2,638,463 of May 'l2, 1953, and can be prepared according to the procedures described therein. molecular weight can be used accordingto the invention but, to obtain films and fibers possessing most. desirable characteristics, the polymer should have afmolecular weight corresponding to a relative viscosity falling within .of anhydrous formic acid; Qncastin'g this solution using [a doctor blade, extremely tough 'films were obtained.

On' dry spinning, this solution gavefilaments. which could be cold'drawn' to fibers having'a tenacity of. 2.5g;

the range 'of 2 to 10, as determined by therelative vis- 5 P r A n a y ,p d Was Obtainedbyspinning intowater or methanol.

cosity of al% solution thereof inmetacr esol. For best. results, the polypyrrolidone utilized should have'a rela-; tive viscosity of between 3.0 and 6.0. V

The formic acid used for dissolving the polypyrrolidone must be anhydrous, or atleast substantially so, e. g.', 98 p to Dissolution of the polypyrrolidone in "the acid can be efiected in any convenient manner, e. g., by simply mixing the polymer and solvent together, prefer ably while heating to a temperature of 30 C. to 50. C., 1 although heat is not essential- 3 Ex (Color Index 1078), and the basic dyestuff Rhodamine It will be understood that various, otherauxiliary agents, normally used by thoseskilled in the, art to modify the properties of film and fiber forming compositions, may be incorporated in the solutions of the invention.

- Similar sol in meta-cresol:gavestrong, tough films and fibers. 7

' Example- IP i III modified to include a 'formic;acid-soluble dyestuif,

'- otherwise desirably colorediifilaments.

dyes and synthetic resins. t V, j p 7 As indicated above, the present compositions are parof except as defined in the appended claims. a

may useful'in the mauctiri of mm which are cha'r I polypyr-rolid'ofri'm filaments and; fibers capable of being -cold-drawn or two-f cludedftherein conventional 'fiber-modifying lag ents, for --fexample, dyestufis ofdesiredshade by which dyeing inv i ofgthe. invention include their application as coatings for I Theinvention, as above described, isfurtherillustrated, 1 The foregoing objects are realized, according to the 25 but not limited, by. the following examples,'-wherein parts This" example illiistra tes' the undesirable resin i'ob-" j done, possess, among other desirable characteristics; exj f 19 o i a tm eti 9?! h ii present- Invention for, d ssolution of therpolypyrrolidone, One part of-{polypyrrolidone (r'elative 'viscosity'of"4 for a l%lsolution in meta -cresol) "is dissolvedrin four parts gof anhydrous" formic acid (98 to 100%}; The re-v ol mer-formic acid solution must be 01 rrolidone, sulting 5 was s as P a a l ow o p y p ypy dry ,at room. temperature: The: thinffoiliobtained was opaque and so weakthat onlyiwith difliculty could it .be

'lln the manner of Example l', 1one part ofipolypyrrolidone, having'the same relative' viscosity, wasdissolved I in three parts, of anhydrous formic acid. Fromthis L f Following the procedure of Example I, a solution of. polypyrmlidone of id 1 varying twoparts of polypyrrolidonewas dissolved inthree parts I p I 7 ns 'm'adexfrom-other polypyrrolidone I having relativeviscosityof 3L'ai1d5 for their 1%. solution i -.Filamentswiere spun from the solution of Example i such as the'acid dyestuff Alizarine Cyanine,Green2G 1 B (Color Index7j49). The results were evenlydyed and TAs'm'anyapparently,widely'diflferent embodiments i ,7 this invention may 'be made-without departingfrom the Typical of such modifying agents are pigmentsffillers, 7o' s'pirit and scope thereof,-,i t isftobe understood that the i invention is not limited to the-specificembodiment there- We claim:

1. A composition of matter comprising polypyrroli done dissolved in at least substantially anhydrous formic acid, said composition containing, in parts by weight, not more than three parts of formic acid per partof polypyrrolidone.

2. A composition as claimed in claim 1 wherein the polypyrrolidone has a relative viscosity of from 2.5 to 16v 3. A composition as claimed in claim 2 wherein the polypyrrolidone has a relative viscosity of from 3.0 to 6.0.

4. A composition of matter suitable for the production or" films and fibers therefrom, said composition comprising polypyrrolidone having a relative viscosity of between 3.0 and 6.0 dissolved in from 1.20 to 3 parts, by weight, of at least substantially anhydrous formic acid per part of polypyrrolidone.

5. A composition as claimed in claim 4 containing 1.5 parts of formic acid per part of polypyrrolidone.

6. A process for producing polypyrrolidone films and the like which comprises applying to a base material a solution of polypyrrolidone in at least substantially anhydrous formic acid, the solution containing, by weight, not more than three parts of formic acid per part of polypyrrolidone and removing the acid solvent.

References Cited in the file of this patent UNITED STATES PATENTS 

1. A COMPOSITION OF MATTER COMPRISING POLYPYRROLIDONE DISSOLVED IN AT LEAST SUBSTANTIALLY ANHYDROUS FORMIC ACID, SAID COMPOSITON CONTAINING, IN PARTS BY WEIGHT, NOT MORE THAN THREE PARTS OF FORMIC ACID PER PART OF POLYPYRROLIDONE. 